Count the line number of file

Question

I just want to count the file lines.

I have googoled around and found two ways but in vane

test = open('./log/test.csv','a')

if sum(1 for line in test) == 0:
    print("no line")

shows

io.UnsupportedOperation: not readable

second way

test = open('./log/test.csv','a')

if len(test.readlines()) == 0:
    print("no line")

it shows error too.

Possible duplicate of [How to get line count cheaply in Python?](https://stackoverflow.com/questions/845058/how-to-get-line-count-cheaply-in-python) — Chris_Rands, Jul 26 '17 at 08:49
You are opening up the file in 'append' mode. How are you expecting to read from it? — SiHa, Jul 26 '17 at 09:03

score 1 · Answer 1 · answered Jul 26 '17 at 08:47

1

try doing:

test = open('./log/test.csv', 'r')

The issue could be you don't have it on read mode

answered Jul 26 '17 at 08:47

dheiberg

AH I see, I wanted to append the lines to this file, so I use `a` value and I thought `a` includes `r` function, now I open file once by `r` mode and then open again with 'a' mode to append lines – whitebear Jul 26 '17 at 08:50

Rahul · Answer 2 · 2017-07-26T09:26:20.770

0

Try removing 'a' in your open function:

with open('file.csv') as f:
    print(len(list(enumerate(f))))

edited Jul 26 '17 at 09:26

answered Jul 26 '17 at 08:48

Rahul

2 Answers2